David Whiteside

Managing Python dependencies in isolated environments is a common practice in software development. But what if you need a quick, temporary virtual environment that you can discard after use? Here’s a simple tool and workflow to create throw-away Python virtual environments.

The Problem

While Python’s built-in venv or tools like virtualenv are excellent for managing environments, they require setup and cleanup. For quick experiments or isolated dependency installations, this process can feel cumbersome.

The init and shutdown commands cleanly shutdown the system by running the shutdown rc scripts.

The advantage of shutdown is that you can set a shutdown delay and warning message.

halt and reboot are not as clean, no shutdown rc scripts are run so applications will not be brought down clean, I generally do not use these commands unless its a last resort.

$ init   # runs the shutdown scripts in /etc/rc*
$ init 0 # shutdown (on sparc it takes it to the ok prompt)
$ init s # single user mode
$ init 5 # shutdown
$ init 6 # reboot

$ shutdown # runs the shutdown scripts in /etc/rc*, prints message warning users
$ shutdown -y -g 0
$ shutdown -y -i 0 # shutdown to ok prompt
$ shutdown -y -i S # single user mode
$ shutdown -y -i 5 # shutdown
$ shutdown -y -i 6 # reboot

$ sync; sync; halt # (ungraceful shutdown, use sync;sync;halt)

$ sync; sync; reboot # (ungraceful reboot. Always run sync;sync;reboot. The prefered method is using init.)
$ sync; sync; reboot -- -r  # reconfiguration reboot
$ sync; sync; reboot -- -s # reboot into single usermode

Maybe you don’t care about the forth programming language, but if you work on Sparc systems long enough you are going to have to work from the ok prompt.

Here are the essentials commands you must know.

Boot the system normally

ok> boot

Boot the system and allow for discovery of new devices (reconfiguration boot)

ok> boot -r

Boot into Single-User Mode

ok> boot -s

Boot into a ROM, useful if your system isn’t bootable